Objective: The anticancer actions of extracts of yacon leaves mainly composed of sesquiterpene lactone were assayed with H22 tumor mice model in vivo and pharmacokinetics of the extracts were also examined. About 200 mg kg–1 of the extracts showed 35.99% tumor inhibitory rate and up-regulation of IL-2 levels and down-regulation of TNF-α. Methodology: High-performance liquid chromatography (HPLC) method was used for the study of pharmacokinetics of enhydrin and uvedalin of the extract with artemisinin as internal standard after oral administration at a dose of 200 and 100 mg kg–1, respectively. Results: Their pharmacokinetics parameters were calculated as follows: The tmax for enhydrin and uvedalin is similar at 1.5±0 h in both doses and Cmax for enhydrin and uvedalin were 13.416±0.210 and 8313.31±0.23 mg mL–1 in high dose and 6.887±0.120 and 4231.45±0.17 mg mL–1 in low dose, respectively. The AUC0→t of enhydrin and uvedalin were 137.444±30.782 and 17345.375±613.231 mg L–1 h–1 in high dose and 43.426±19.663 and 8831.724±555.122 mg L–1 h–1 in low dose, respectively. Conclusion: The anti-cancer action of sesquiterpene extracts of yacon leaves was explored. Further, a simple and specific HPLC method was developed for the determination of enhydrin and uvedalin from yacon leaves extract in rat plasma. This study laid a foundation for the further utilization of yacon leaves.